PYONGYANG, North Korea -- China's top negotiator on North Korea's nuclear programs has arrived in Pyongyang.

No details of the purpose of the trip, which began Monday, were immediately announced by North Korea or China.

Wu Dawei is the Chinese Foreign Ministry's special representative for Korean Peninsula affairs and has previously chaired rounds of six-nation talks in Beijing which bring together North and South Korea, China, the U.S., Japan and Russia for negotiations on North Korea's nuclear ambitions.

It is Wu's first known visit to Pyongyang this year, and the first since North Korea surprised the world by executing one of its top officials, Jang Song Thaek, last December. Wu made at least two trips to Pyongyang in August and November last year.